OMS 3250

OMS3250Product DescriptionLO-VC Switch Up to 32 Provides the LO-VC switching subsystem and tributaryinterfacesLTU PSU 2 Provides derived voltage to the LTUs (also providesV.11/G.703 Auxiliary interfaces)Battery LTU 2 Provides filtered subrack feed voltage to the cards LTUPSUs and fans.Management LTU 1 Provides physical connectors for Q interface, F interface,and extension subrack (also provides EOW interface)Sync LTU 1 Provides external synchronisation input and outputinterfaces (also provides Ground contact and rack alarminterfaces)Fan tray unit 5 or 10 Maintains correct environmental temperatureOptional unitsPrimary Switch Unit 1 Provides protection.Secondary Switch Unit 3 Provides protectionContr/Comms Unit1 (including2 SMC)Provides protection.Auxiliary Unit 1 Provides communication channels for service functions11.1.1 SDH Tributary UnitsIn OMS3250, the SDH tributary units perform the following functions:• optical/electrical interface;• SOH insertion/extraction;• AU-4 mapping/demapping;• VC-4 POH supervision; this function can be activated/deactivated by the user;• selection of one of the two data streams received from the switch by means ofinsertion/monitoring of check messages.In order to guarantee a high level of availability the Electrical Tributary Unit can be cardprotected.The card protection schemes are:• two groups of electrical tributary cards can be 1:N protected, with N up to 4.• 1:N card protection is REVERTIVE.Issue 1 Copyright – Refer to Page 2 Page 47 of 74